bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Roughness on Lipophobicity of a Surface Prepared Using Boehmite Nanoparticles and Fluoroalkylsilane
Authors: Nakajima Akira , Hoshino Mitsuhiro , Song Jeong-Hwan , Kameshima Yoshikazu , Okada Kiyoshi
Published: May 2005

The effect of surface roughness on lipophobicity was investigated on a surface prepared using a combination of boehmite nanoparticles and fluoroalkylsilane. The requirement of surface roughness for superlipophobicity by oleic acid is higher than 565 nm when the surface energy is approximately 14 mJ/m2. This roughness value is around ten times of that for superhydrophobicity.
Synthesis of Tetrakis(2-furyl)methane
Authors: Kurata Hiroyuki , Oki Yoshiaki , Matsumoto Kouzou , Kawase Takeshi , Oda Masaji
Published: May 2005

The parent tetrakis(2-furyl)methane is first synthesized using aromatic nucleophilic substitution on 2-chlorofurans as a key reaction. X-ray analysis reveals the shortest bond length between the central methane carbon and furyl ipso-carbons among known tetraarylmethanes. Successful tetrabromination and tetralithiation promise its high synthetic utility.
NMR Study of the Amide Bond-formation Using a Heterocyclic Amine and Acid Receptor
Authors: Condamine Eric , Moore Grégory , Marsais Francis , Dupas Georges , Papamicaël Cyril , Levacher Vincent
Published: May 2005

Recently, a tricyclic receptor capable of binding a carboxylic acid or an amine has been described. A kinetic study of the reaction between benzoic acid and benzylamine to give the amide bond using this heterocyclic receptor has been performed. The results suggest that the receptor plays a significant role in accelerating the amide bond-formation. To gain further information on the complex formation between the host, benzoic acid and benzylamine, NOESY and T-ROESY experiments were performed.
Does Low Frequency Noise at Modarate Levels Influence Human Mental Performance?
Authors: Pawlaczyk-łuszczyńska Malgorzata , Dudarewicz Adam , Waszkowska Małgorzata , Szymczak Wiesław , Kameduła Maria , Śliwińska-Kowalska Mariola
Published: May 2005

The aim of this study was to assess the influence of low frequency noise (LFN) at levels normally occurring in the industrial control rooms on human mental performance (attention, visual perception and logical reasoning) and subjective well-being.

Subjects were 191 male volunteers categorised in terms of subjective sensitivity to noise in general. They performed standardised tests: the Signal Detection Test (test I), the Stroop Colour-Word Test (test II), and two sub-tests of the General Aptitude Test Battery, i.e. the Math Reasoning Test (test III) and the Comparing of Names Test (test IV). Three different acoustic conditions were used in the between-subjects design: the background laboratory noise of about 30 dB(A), LFN, and a broadband noise without dominant low frequency components (reference noise) at 50 dB(A). Each subject was tested only once in random-assigned exposure conditions.

Generally, no significant differences in performance related to exposure conditions were noted. Some of the results from test I and test II were influenced by sensitivity to noise. However, there were no significant differences between high- and low-sensitive subjects during exposure to LFN.

The annoyance of LFN and reference noise was rated higher than that of the background noise. Subjects highly-sensitive to noise reported higher annoyance due to LFN in comparison with low-sensitives. No significant differences related to noise sensitivity in annoyance assessment of background and reference noises were noted.

In conclusion, no effects due to LFN on mental performance compared to background and reference noises were found.
Estimation of Acoustical Performance of Floating Floors from Dynamic Stiffness of Resilient Layers
Authors: Schiavi Alessandro , Belli Andrea Pavoni , Russo Francesco
Published: May 2005

This paper describes a procedure for evaluating the reduction in impact sound pressure level of floating floors by measuring the apparent dynamic stiffness of the resilient layer, according to International Standard EN 29052-1. The impact sound pressure level experimental data, obtained according to International Standard UNI EN ISO 140-8, was compared with estimates obtained from dynamic stiffness measurements. Results confirm the effectiveness of the empirical model. Two questions are addressed. The first concerns the decrease in layer thickness over time. The second concerns the relationship between damping ratio and performance.
Optimization and Dynamic Analysis of Frame Structures with Friction Energy Dissipation Device
Authors: Xu Yuye , Wu Bo , Wang Quanfeng
Published: May 2005

An analytical solution for a single-damped-storey frame structure system including a friction energy dissipation device under sine wave excitation is presented with an example. A new mathematical model for optimizing some key system parameters in earthquakes is proposed. The model minimizes the sum of brace stiffness that complies with the Chinese seismic code for storey-drift limitations for three given earthquake records. Therefore, the seismic requirements for similar structures can be satisfied with fewer friction energy-dissipation devices. Using the Visual C++ language, a computer program, GAOFF, has been developed to optimize the parameters of a frame structure with friction energy dissipation devices based on three earthquake records using a genetic algorithm. An example of a six-storey RC frame is also presented to demonstrate the effectiveness of the proposed optimal design procedure.
Stress Singularity Effect on Beam Flanges in Moment Connections
Authors: Hsiao J. Kent , Chambers Janice J. , Schultz William J.
Published: May 2005

The ductility capacity of the directly welded flange connection was found to be insufficient after the 1994 Northridge earthquake. The Enlarged End Section (EES) connection which considers the stress singularity effect on beam flanges can be utilized as a means to improve the performance of welded moment connections. The corner of a steel plate contains stress singularities (unbounded stresses) when the corner is bounded by free-free edges and when the angle of the corner is larger than 180°. Also, the corner of a steel plate contains stress singularities when the corner is bounded by fixed-free edges and when the angle of the corner is larger than 61.3°. Nonlinear static finite element analyses of two types of beam-to-column moment connections were conducted. These two types of connections are (1) the constant-beam-section connection, and (2) the Enlarged End Section connection. The result of the finite element analyses shows that the Enlarged End Section connection exhibits much higher strength and ductility capacities.
Puttin’ on the Sting: Women Police Officers' Perspectives on Reverse Prostitution Assignments
Authors: Dodge Mary , Starr-Gimeno Donna , Williams Thomas
Published: June 2005

Reverse police prostitution stings, which target men by using female police officers as decoy prostitutes, are becoming a common method in some United States cities for controlling the problem of solicitation for prostitution. The role of policewomen as decoys has received scant attention by scholars, though critics and traditional feminists view the practice as further evidence of the subjection and degradation of women in law enforcement. This article presents participant field observations of how reverse prostitution operations are conducted in Aurora, Colorado Springs, and Denver, Colorado and qualitative interview data from 25 female police officers who discuss their experiences as prostitution decoys. The findings indicate that female officers view the decoy role as an exciting opportunity for undercover work, despite the negative connotations of acting like a whore. According to the officers who work as decoys, it adds excitement and variety and offers potential for other opportunities for advancement within the police department in contrast to the rather mundane duties often associated with patrol.
Step-Scan Fourier Transform Infrared Study on the Effect of Dynamic Strain on Isotactic Polypropylene
Authors: Budevska Boiana O. , Manning Christopher J. , Griffiths Peter R. , Roginski Robert T.
Published: June 2005

Dynamic rheo-optical spectra of two isotactic polypropylene samples of different states of order were measured by step-scan FT-IR spectrometry. Experimental details and data collection considerations are discussed. The features in the dynamic spectra are found to be due to small wave-number shifts and absorption changes. The dynamic rheo-optical spectra depend strongly on the pretreatment of the samples, as well as on the polarization state of the infrared radiation used for analysis.
Simple Technique for Measuring Surface-Enhanced Fourier Transform Raman Spectra of Organic Compounds
Authors: Roth E. , Hope G. A. , Schweinsberg D. P. , Kiefer W. , Fredericks P. M.
Published: June 2005

A silver surface, suitable for Fourier transform surface-enhanced Raman scattering (FT-SERS), has been prepared by subjecting a polished silver surface to an oxidation-reduction cycle in an electrochemical cell with KCl solution as the electrolyte. The surface produced by this method is shown, by scanning electron microscopy, to be very rough. The preparation of this surface is quite reproducible because the significant parameters of starting surface, electrolyte concentration, and potential can all be well controlled. After removal from the cell followed by washing and drying, organic compounds can be placed on the surface as solutions in aqueous or organic solvents, or by exposure of the surface to vapor. Typically, good FT-SERS spectra are obtained from 0.1–2 μg of sample, after evaporation of the solvent. These experiments were not optimized for minimum detection limits. The technique is very simple, and spectra can be obtained with ease for a wide variety of compounds. Most compounds gave FT-SERS spectra which were similar to their solid Raman spectra; however compounds containing groups expected to interact strongly with the silver surface gave FT-SERS spectra very different from their normal Raman spectra.
Laser-Based Solid-Matrix Fluorescence of Stereoisomeric Tetrols
Authors: Shu L. , Hurtubise R. J.
Published: June 2005

A laser-based fluorescence measurement system was constructed and used to obtain solid-matrix fluorescence spectra from four stereoisomers. The four isomers were tetrols which are products from benzo(a)pyrene-DNA adducts. The laser-based system showed unique advantages in obtaining the fluorescence fine structure from the tetrols in comparison to non-laser-based commercial spectrofluorometers. A new gatewidth dependence method was developed with the laser system that can be used to characterize and identify the stereoisomers adsorbed on α-cyclodextrin/NaCl at room temperature. The basis of the new gatewidth method depends on different interactions of the analyte molecules with the solid matrix. The method developed has the potential for general analytical application for the identification and characterization of fluorescent stereoisomers and other fluorescent compounds.
Spectroscopic Investigation of Fluorescence Quenching Agents. Part IV: Selectivity of Nitromethane for Discriminating between Alternant versus Nonalternant Polycyclic Aromatic Hydrocarbons in Solvents of Differing Polarities
Authors: Tucker Sheryl A. , Bates Heather C. , Acree William E. , Fetzer John C.
Published: June 2005

To further assess the applicability of nitromethane as a selective quenching agent for alternant vs. nonalternant polycyclic aromatic hydrocarbons in HPLC analysis, we measured the effect that it has on the fluorescence emission behavior of 96 different polycyclic aromatic hydrocarbons dissolved in a binary ethyl acetate/acetonitrile solvent mixture. Nitromethane quenching results are compared with previously reported acetonitrile, aqueous/acetonitrile, and toluene/acetonitrile solvent mixtures. Results of these measurements revealed that the “selective quenching” rule is obeyed for the vast majority of PAHs in all solvents considered thus far, with the coronene derivatives being the only major exceptions.
Enhancement of Total Reflection X-Ray Fluorescence Spectroscopy with Electrochemical Deposition
Authors: Fan Qiang , Gohshi Yohich
Published: June 2005

An electrodeposition preconcentration technique was used in conjunction with total reflection x-ray fluorescence (TRXRF) analysis. Enhancement in sensitivity on the order of 103 was realized for the ions investigated here. In addition, x-ray scattering was reduced and a degree of selectivity was achieved by the electrodeposition. The results suggest that trace elemental analysis (sub-ppb level) with chemical speciation capability is feasible by using TRXRF with a conventional x-ray source.
Axial Transmissive f/1.8 Imaging Raman Spectrograph with Volume-Phase Holographic Filter and Grating
Authors: Battey David E. , Slater Joseph B. , Wludyka Ronald , Owen Harry , Pallister David M. , Morris Michael D.
Published: June 2005

An axial transmissive Raman spectrograph is described. The instrument employs volume-phase holograms as the laser line rejection filter and transmission grating. The on-axis configuration and the use of a high-spatial-frequency transmission grating allows nearly diffraction-limited imaging and pixel-limited resolution at f/1.8. The performance of the instrument is demonstrated for fiber-optic probe and microprobe Raman spectroscopy.
Laser-Induced Fluorescence Multicomponent Analysis in Full Spectra and Their Fourier Transforms by Principal Component Regression
Authors: Chang Kaisyang , Brown Chris W. , Forcé R. Ken
Published: June 2005

Laser-induced fluorescence spectroscopy (LIFS) has been used to analyze two- and three-component systems. Equations describing the fluorescent emission process have been incorporated into the Beer's law absorption analog to make multicomponent analysis applicable to LIFS. Principal component regression (PCR) has been employed to predict concentrations of components having severe peak overlap. Results obtained from using a pulsed nitrogen laser and a cw argon-ion laser as excitation sources are compared in order to elucidate some of the important features in applying fluorescence for multicomponent analysis. Furthermore, PCR analysis was also applied to Fourier transformed fluorescence spectra with the use of only 8 and 16 Fourier terms for prediction. The improvements from the Fourier processing are 50.1% and 19.8% in a two-component system, and 22.4% and 8.3% in a three-component system, for cw and pulsed laser excitation, respectively. The time required for calibrating with the Fourier transformed fluorescence spectral data is dramatically reduced to 67 s compared to 551 s for wavelength domain data. Multicomponent analysis of the four dyes (FITC, NBD, TMRITC, T.RED) and dye-amine conjugates used in fluorescence-based DNA sequencing, as well as the analysis of a highly overlapped polyaromatic hydrocarbon (pyrene, anthracene, fluoranthene) system is demonstrated. Standard error of prediction (SEP) values for cross-validation calculation of all training sets were <5%. When applied to time-resolved fluorescence measurements, multicomponent analysis can provide an alternative means of resolving fluorescence peak overlap output as numerical representations, especially in mixtures where components have similar fluorescence lifetimes and overlapped spectra.
Saha-Boltzmann Statistics for Determination of Electron Temperature and Density in Spark Discharges Using an Echelle/CCD System
Authors: Bye Cheryl A. , Scheeline Alexander
Published: June 2005

A custom echelle/CCD spectrometer system has been employed for equilibrium and nonequilibrium excitation measurements in the high-voltage spark discharge. By exploitation of the large spectral information bandwidth of the echelle/CCD system, multiple ionization stages of argon were observed in the spark emission spectrum. Ion-to-atom emission intensity ratios were used in a linearized form of the coupled Saha-Boltzmann equation for the determination of both electron temperature and density. Nonequilibrium conditions were considered. The dependence of argon excitation on sample matrix was also explored.
Optically Dilute, Absorbing, and Turbid Phantoms for Fluorescence Spectroscopy of Homogeneous and Inhomogeneous Samples
Authors: Durkin A. J. , Jaikumar S. , Richards-Kortum R.
Published: June 2005

This paper presents a phantom which simulates the optical properties of tissue. The phantom absorption coefficient, scattering coefficient, anisotropy factor, and fluorescence quantum yield can be independently varied to investigate the effects of these parameters on fluorescence excitation and emission spectra from 300 to 650 nm. Phantom fluorophores include Flavin Adenine Dinucleotide (FAD) and Rhodamine B. Absorption is controlled by adjusting phantom hemoglobin concentration. On the basis of their smoothly varying scattering coefficient and the relatively low amount of fluorescence contributed to the mixture in comparison to other available scatterers, 1.05-µm-diameter polystyrene microspheres were selected as a scatterer. Sample inhomogeneities are simulated by preparing the phantom in a gelatin substrate. The optical properties of turbid phantoms determined with the use of indirect techniques agree well with known values as long as µs(l – g) > µa. Data are presented from dilute, absorbing, and turbid phantoms and inhomogeneous phantoms to qualitatively illustrate the effects of optical properties and sample geometry on fluorescence spectra. The phantom provides the framework for detailed quantitative investigations of the effects of optical properties, sample size, shape, and structure, boundary conditions, and collection geometry on fluorescence spectra.
Potential of Fourier Transform Near-Infrared Spectroscopy in Studies of the Dissociation of Fatty Acids in the Liquid Phase
Authors: Czarnecki Mirosław Antoni , Liu Yongliang , Ozaki Yukihiro , Suzuki Masao , Iwahashi Makio
Published: June 2005

Fourier transform near-infrared (FT-NIR) technique has been employed to determine the degree of dissociation and the thermodynamic parameters of octanoic acid in the liquid phase. FT-NIR absorption spectra of the acid over a temperature range of 15 to 92°C were recorded. From the spectra, intensities of the first overtone of the OH stretching mode due to the monomer form of the acid were extracted and were used to calculate the degree of dissociation and the thermodynamic parameters for the process of dissociation of dimeric octanoic acid into monomer species. In the 7400–6700 cm−1 region there appear many bands that are heavily overlapped; the attempts to apply curve-fitting and deconvolution algorithms to separate individual bands have failed. Here, a simple and reliable method of calculation of the intensities of the first overtone of the OH stretching mode due to the monomer is proposed. Also, an excellent procedure of determining the molar absorption coefficients (integrated and at peak position) through a series of measurements in CCl4 solution at very low concentrations is presented. The bands due to CH vibrations were eliminated in two ways; one way involved taking the concentration as a reference, and the other used the band area of the second overtone of the CH stretching modes as a reference. In the operation the spectrum of neat octanoic acid at 15.1°C was employed. The coefficients obtained by both methods are compared and discussed. The present studies indicate that both band areas and peak heights give results which are found to be in very good agreement.
Laser-Induced Fluorescence Imaging of Paper Surfaces
Authors: Häkkänen H. J. , Korppi-Tommola J. E. I.
Published: June 2005

Laser-induced fluorescence imaging has been used to study the microstructure of paper surfaces. Pulses from a XeCl-excimer laser, 10 ns in duration at 308 nm, were used for excitation, and fluorescence was collected at 420 nm. The excitation spot diameter was approximately 20 µm, and the sampling interval 0.15 mm. Within an area of 5*5 mm2, 1023 sampling points were recorded to generate 3D fluorescence maps of paper surfaces. Papers containing fluorescence whitening agents (FWAs) gave the highest average fluorescence signals. Coated papers with no FW As show weaker signals than the base sheet. For some thirty different paper samples, an obvious correlation between the amount of coating and the average intensity of the fluorescence signal was observed. Signal fluctuations around the average intensity values were sensitive to (1) the chemical pulp content in super calantered (SC) paper, (2) the amount of recycled fiber in newsprint, and (3) the amount of coating on the light-weight coated (LWC) paper surface. An effort was made to correlate fluorescence imaging results to predict mottling (diffusion of printing ink after printing) in various paper brands.
Diode Array Spectrometer for Nitrogen Isotopic Analysis
Authors: Lipschultz Fredric
Published: June 2005

The analytical precision for measurements of the isotopic composition of dinitrogen gas by emission spectrometry has primarily been limited by variability of the spectral background. Imaging the spectral region surrounding the isotopic bandheads with a diode array permitted a correction to be made for the background spectra and increased the statistical precision of the raw data. With the use of a multiple regression algorithm to process the spectral data, the standard deviation for an individual determination at the natural abundance level was 0.002 atom %. After an initial calibration, the standard deviation for measurements of the same sample, repeated over several years, remained at that level. In contrast to the case for commercial instruments, samples of widely varying mass can be readily analyzed. Further increases in precision are limited by an unidentified source of variance.
Atomic Emission Spectrometry Employing a Pulsed Radio-Frequency-Powered Glow Discharge
Authors: Pan Changkang , King Fred L.
Published: June 2005

A radio-frequency (rf)-powered glow discharge pulsed at 50 Hz with a 25% duty cycle is used as an atomization/excitation source for analytical atomic emission spectrometry. Compromise working conditions are established at 0.8 Torr argon pressure and 80 to 90 W peak applied power. Analyte emission intensities are found to increase with increases in discharge pressure and peak applied rf power to an upper limit corresponding with the onset of discharge instability. The observed emission signal intensity is influenced strongly by changes in the cathode-to-anode separation distance. Long-term analytical signal stability is exhibited by this source at rf powers up to 90 W in the absence of external cooling because of operation in the pulsed mode. The maximum attainable stable emission signal with pulsed operation is approximately four times greater than that attainable with steady-state operation. The analytical utility of this source is demonstrated through determinations of trace elements in coal fly ash and graphite samples with limits of detection in the tens of parts-per-million range.
Study of Solute Influences on the Binding of Metals to Stichococcus Bacillaris with 113Cd NMR
Authors: Zhang Weixing , Majidi Vahid
Published: June 2005

The interaction between a unialgal species ( Stichococcus bacillaris) and cadmium in the presence of several different solutes was investigated by 113Cd NMR. The interaction between the algae and cadmium was very strong, and the Cd/algae complex has an average formation constant of 2.8 × 10s. Upon addition of different solutes into the algae suspension, two results were obtained: in some cases the cadmium in the Cd/algae biomass was removed, and in other situations water molecules around the bound cadmium were replaced by the added ligands. When the Cd/algae biomass was suspended in acetic acid or sodium acetate buffer solutions, some of the bound cadmium was released, but only one resonance was observed for both the Cd/algae complex and the free cadmium in the solution. This chemical shift similarity indicates that the predominant functional group on the cell wall of S. bacillaris is carboxylate. Gold(III) was also found to strongly interact with S. bacillaris.
Laser-Based Double-Beam Circular Dichroism Detector for Liquid Chromatography
Authors: Rosenzweig Zeev , Yeung Edward S.
Published: June 2005

A highly sensitive and selective double-beam laser-based circular dichroism (CD) detector for high-performance liquid chromatography (HPLC) is presented. An all-electronic noise canceller circuit was used to subtract the intensity of the right circularly polarized light from the intensity of the left circularly polarized light. Both of these beams were derived from the same Ar-ion laser operated at 488 nm. The chiral inorganic complexes of tris(ethylenediamine)cobalt(III), Co(en)33+, which are CD active at this wavelength [Δɛ(488 nm) = 1.9 cm2 mol−1], were chosen as test compounds. The two enantiomers were chromatographically separated from the corresponding racemic mixture through the use of potassium antimonyl(III) tartrate hydrate and ion-pair reversed-phase liquid chromatography. A practical noise-to-signal ratio of 4 × 10−6 for CD measurements was achieved despite the presence of the high background absorption, which is 45 times higher than the CD signal for this particular system. The detector is linear through two orders of magnitude (10−3 M-10−5 M). The deviation between consecutive measurements is less than 5% and the noise level is 1.8 × 10−6 AU. A limit of detection (LOD) of 1.2 × 10−6 M at the flow cell, which corresponds to 25 ng injected material, was achieved. This value is similar to the LOD that was obtained for the same species by using laser-based high-frequency modulation and is only 3.5 times worse than thermal-lens CD detection. Being simpler and less expensive than other laser-based systems, our double-beam HPLC-CD detector provides a three-orders-of-magnitude improvement in sensitivity as compared to that for conventional CD spectrometers.
Analyte Matrix Excitation Investigations in the High-Voltage Spark Discharge Using an Echelle/CCD System
Authors: Bye Cheryl A. , Scheeline Alexander
Published: June 2005

The matrix dependence of analyte excitation in the high-voltage spark discharge has been investigated. The analyte excitation distributions of Fe(I), Mo(I), and Cu(I) have been measured. The large wavelength range of a custom echelle/CCD system was exploited for these determinations. The analyte excitation within the high-voltage spark on a time-integrated basis was determined to be independent of both sample matrix and sampled species.
Determination of the Principal Direction of Molecular Orientation in FT-IR Measurement Using Two Polarizers
Authors: Cao Bangshu , Mar Kevin
Published: June 2005

An optical arrangement using two polarizers is proposed for FT-IR measurement of orientation. Compared with conventional FT-IR using a single polarizer, the new arrangement provides much better discrimination in searching for the principal directions of orientation.
On the Correlation between Electronic Spectra of Alternant Aromatic Hydrocarbons and Their Radical Cations
Authors: Khan Zahid H. , Husain Mudassir M. , Haselbach Edwin
Published: June 2005

On the basis of the spectroscopic data for some 40 alternant aromatic hydrocarbons, a simple correlation is given between the excited singlet state ( p band) of such molecules and the excited lowest-energy non-Koopmans state ( A band) for their radical cations. It is shown that, with the use of this relation, the energy of the doublet state for a radical cation can be reasonably estimated if the energy of the p band for its neutral precursor is known. We have also computed the doublet state energies of the aromatic hydrocarbons using the “SDT” relations, which involve three spectroscopic quantities, viz., the excited singlet ( S) and triplet ( T) states of a neutral molecule and the doublet ( D) state of its radical cation. The predictions of the proposed singlet-doublet state correlation are found to be far superior than those of the SDT relations.
Thermal Lens Study of the Absorbance of Silver Colloid Solutions Produced by Photoreduction
Authors: Zhang Zhengming , Long George R.
Published: June 2005

The absorption of light by photolytically generated silver colloid solutions is studied by thermal lens spectrophotometry. It is found that absorbance by silver nitrate solutions at 488 nm is a result of colloid formation. The absorbance is related to the particle size distribution and varies substantially from measurement to measurement even within the same colloidal solution. The shot-to-shot variance of the thermal lens signal is minimized by producing the colloid in a flowing AgNO3 solution, but still varies significantly from solution to solution at equal concentrations.
Microscopic Identification of Silicone in Human Breast Tissues by Infrared Microspectroscopy and X-Ray Microanalysis
Authors: Centeno Jose A. , Johnson Frank B.
Published: June 2005

Fourier transform infrared (FT-IR) microspectroscopy has been employed for the identification of silicone fragments in human breast tissue. Tissue specimens were mounted on aluminum-or gold-coated microscope slides and analyzed by employing the reflectance capabilities of the infrared microscope. Scanning electron microscopy (SEM) and energy-dispersive x-ray microanalysis (EDXA) were also used to establish the elemental composition and location of the foreign material. Infrared absorptions originating from the Si-O bond were easily identified at 1097 and 1017 cm−1, whereas the methyl group (-CH3) symmetric deformation mode arising from the Si-CH3 group was observed at 1260 cm−1. Being a nondestructive technique, infrared microscopy may serve as a highly suitable tool for the routine and accurate identification of silicone particles in various pathological specimens.
Optically Active Vibrations of Doped Lanthanum Copper Oxide Compound (La2−xMxCuO4)
Authors: Ohwada Ken , Fujisawa Ginji
Published: June 2005

Normal coordinate analysis of the optically active vibrations of doped lanthanum copper oxide (La2– x M xCuO4) has been made, with the assumption of an infinite [(CuO2)O2]6– layer model. On the basis of the results of this treatment, some of the observed bands so far reported have been successfully assigned to the Cu-O lattice vibrations. The force constants concerning Cu-O bonds have been obtained within the framework of a modified valence force field. It has been found that the present analysis based on the infinite layer model is useful for assigning the relatively high vibrational frequencies observed at the center (wave vector k = 0) of the first Brillouin zone in La2– x M xCuO4.
Radioisotope-Excitation XRF Determination of Trace Elements in Marble
Authors: Yap C. T.
Published: June 2005

The energy-dispersive x-ray fluorescence technique was employed to determine quantitatively the concentrations of trace elements in 22 pieces of thick marble of various sizes from Portugal and Thailand, with the use of the radioactive sources Fe-55, Cd-109, and Am-241 in order to cover a wide range of elements. The reliability of the concentration determination was confirmed by employing two different methods which gave the same quantitative values of iron within experimental errors. The following trace elements were found to be present in varying concentrations: manganese (0–244 ppm), iron (110–4104 ppm), copper (14–64 ppm), zinc (0–665 ppm), arsenic (0–27 ppm), strontium (100–335 ppm), and yttrium (0–12 ppm). It was found that, besides iron, which is responsible for the staining or coloring of marbles, manganese can cause dark streaks and colored patches and has values as high as 244 ppm. With the use of iron, yttrium, and strontium in a triangular plot, the pieces from Portugal and Thailand, respectively, divided into two well-defined groups which are well separated from each other, showing that it is possible to identify the origin of the marble pieces.
Surface-Enhanced Resonance Raman Spectra Study of α,β,γ,δ-Tetra-(4-Trimethyl Ammonium Phenyl) Porphyrin
Authors: Chen Jian , Hu Ji-Ming , Xu Zhi-San , Sheng Rong-Sheng
Published: June 2005

In the present study, surface-enhanced resonance Raman scattering (SERRS) spectra of α,β,γ,δ-tetra-(4-trimethyl ammonium phenyl) porphyrin [T(4-TAP)P] were obtained. With increasing pH, the relative intensities of the bands at 890 and 1244 cm−1 decreased. These bands were attributed to γ(C-H) and δ(Cm-phenyl), respectively. The bands at 420 and 576 cm−1, which were assigned to γ(phenyl-ring), were enhanced. The molecular symmetry of T(4-TAP)P is discussed in terms of group theory. The bands at 1554 and 1496 cm−1 could be attributed to the vibrational modes of the porphyrin macrocycle; the bands at 1460, 1362, and 1330 cm−1 were assigned to ν(C-C) + δ(C-H), ν(C-N) + δ(C-H), and ν(C-N), respectively. All these bands change in band intensities, positions and widths, with the potential changing from +0.2 V to −0.2 V. It was concluded that the adsorbed porphyrins underwent partial incorporation with Ag from the electrode, and the adsorbate assumed a flat orientation on the silver electrode as well as the Ag colloid surface.
Comparison of Beer's Law and Thermal Lens Techniques for Absorption Measurements under Conditions of High Scattering Backgrounds
Authors: Thorne John B. , Bobbitt Donald R.
Published: June 2005

Thermal lens spectroscopy has been experimentally compared to the conventional Beer's law method in situations where the sample under study possesses substantial light-scattering properties. Large errors in the measured absorbance were found with the conventional transmission-based approach. However, the thermal lens method was found to provide significant experimental immunity from the effect of light scattering on the measurement process. Both the absorbance and light-scattering properties of the samples tested were varied over a range in excess of an order of magnitude. The thermal lens method provided absorbance values for all samples tested which were as good as those obtained for samples that did not possess scattering characteristics. The results demonstrate that the immunity from light-scattering perturbations is substantial, thereby eliminating the need to match the scattering properties of standards and unknowns for accurate quantitation. The experimental results are compared to theoretical predictions and found to be in good agreement.
Analytical Feasibility of Graphite Rod Vaporization-Helium Microwave-Induced Plasma (GRV/He-MIP) for Some Nonmetal Determinations
Authors: Abdillahi M. M.
Published: June 2005

Trace level quantities of some nonmetallic elements are determined by coupling graphite rod electrothermal vaporization with a helium microwave-induced plasma. Microliter liquid samples of chlorides, bromides, iodides, sulfides, and ammonium nitrogen have been introduced into a grooved graphite rod, where they were dried, ashed, and vaporized into the plasma. The analytical performance of the GRV/He-MIP was found to be an excellent excitation source for dry analyte vapors. The graphite rod vaporization device is well suited for sample introduction for a lowpower microwave-induced plasma. Analytical calibration curves were obtained that have linearities between 2.5 to 5 orders of magnitude. Detection limits of the technique for 10- μL aqueous sample solutions are reported in the lower nanogram region. The common anions and cations did not show significant interference effects on the determination of traces of these nonmetals.
FT-IR/ATR Study of Lithium Intercalation into Molybdenum Oxide Thin Film
Authors: Badilescu Simona , Boufker Khalid , Ashrit P. V. , Girouard Fernand E. , Truong Vo-Van
Published: June 2005

Molybdenum oxide thin films are deposited by thermal evaporation and sputtering, and lithium is inserted by a dry lithiation method. The FT-IR/ATR technique is used to study the formation and evolution of lithium bronze and lithium molybdate species. The mechanism of lithium intercalation is found to be dependent on the method of film preparation. The involvement of water molecules in the kinetics of lithiation is stressed.
Spectroscopic Investigation of Fluorescence Quenching Agents. Part III: Effect of Solvent Polarity on the Selectivity of Nitromethane for Discriminating between Alternant versus Nonalternant Polycyclic Aromatic Hydrocarbons
Authors: Tucker Sheryl A. , Acree William E. , Fetzer John C. , Harvey Ronald G. , Tanga Mary J. , Cheng Pei-Chao , Scott Lawrence T.
Published: June 2005

To better assess the applicability of nitromethane as a selective quenching agent for alternant versus nonalternant polycyclic aromatic hydrocarbons in HPLC, TLC, and HPTLC analysis, we measured the effect that it has on the fluorescence emission behavior of 96 different polycyclic aromatic hydrocarbons dissolved in binary toluene/acetonitrile solvent mixtures. Results of these measurements revealed that the “selective quenching” rule is obeyed for the vast majority of PAHs, with the coronene derivatives being the only major exceptions. Fluorescence emission spectra are also reported for benzo[g]chrysene, naphtho[2,3g]chrysene, 4 H-benzo[c]cyclopenta[mno]chrysene, dibenzo[ghi,mno]fluoranthene (commonly called corannulene), rubicene, diacenaphtho[l,2j:l‘,2'l]fluoranthene, 10-methyl-benzo[b]fluoranthene, 3-methoxybenzo[k]fluoranthene, and 3-hydroxybenzo[k]fluoranthene in organic nonelectrolyte solvents of varying polarity. Calculated emission intensity ratios failed to vary systematically with solvent polarity, and all nine of the aforementioned solutes were thus classified as nonprobe molecules.
Measurement of Water Vapor Pressure and Activity Using Infrared Diode Laser Absorption Spectroscopy
Authors: Bone S. A. , Cummins P. G. , Davies P. B. , Johnson S. A.
Published: June 2005

A mid-infrared laser technique is described for the accurate determination of water vapor concentration in the headspace above a liquid sample. The method is based on the measurement of the fractional absorption, at line center, of a single ro-vibrational line. A dual-beam optical arrangement, incorporating a reference vapor cell, is used to provide an active calibration for the measurement. It is shown how the absorption signals can be related to the water activity of a liquid sample. The technique has the advantages of being noninvasive, rapid, and signal-specific to water. It does, however, intrinsically have a nonlinear response to activity. This drawback is mainly a consequence of pressure broadening, and has limited the present measurements to sample temperatures in the range 268 to 293 K. In this regime the method gives a precision of ±1% for activities near unity. This limit is imposed by small fluctuations in certain environmental variables. Suitable modifications should enable operation at the ±0.1% level of accuracy over an extended temperature range.
Influence of Water on Spatial Excitation Behavior in the DCP
Authors: Niemczyk Thomas M. , Chu Chi-Ping
Published: June 2005

Spatially resolved excitation temperatures and electron densities in the direct-current plasma (DCP) have been measured as a function of the amount of water introduced to the plasma. Both the excitation temperature and the electron density increase with the quantity of water introduced. The increase in these parameters is large for very low water introduction rates, but slows as the amount of water introduced is increased. A plateau is reached where the amount of water introduced no longer affects the electron concentration or excitation temperature. This plateau is reached at a water introduction rate significantly less than that normally used for routine analytical work.
Raman Spectroscopic Characterization of Human Breast Tissues: Implications for Breast Cancer Diagnosis
Authors: Redd Douglas C. B. , Feng Zhe Chuan , Yue Kwok To , Gansler Ted S.
Published: June 2005

Development and application of laser-based diagnostic and therapeutic procedures have been hindered by the current technical inadequacies in tissue diagnosis and characterization. It is now possible to apply the techniques of Raman spectroscopy to achieve rapid, noninvasive, and nondestructive differentiation of diseased from normal tissues. Normal and diseased breast tissues were examined by Raman spectroscopy. The Raman spectra obtained contain features that are attributable to various amounts of carotenoids and lipids. A small contribution from a heme-type signal was detected in some samples of clinically abnormal yet histopathologically benign breast tissue, while a much stronger heme-type signal was detected in most of the breast cancers. Raman spectra of diseased breast tissue (benign and malignant) also show markedly diminished to absent contributions from lipids and reduced contributions from carotenoids. This laser-based spectroscopic modality is readily adaptable to reflected light microscopy and optical fiber techniques, making it potentially useful as an aid in real-time diagnosis, and may thus find application in the fields of histopathology and interventional radiology.
Spatially Resolved Measurements of Size and Velocity Distributions of Aerosol Droplets from a Direct Injection Nebulizer
Authors: Shum Sam C. K. , Johnson Steve K. , Pang Ho-Ming , Houk R. S.
Published: June 2005

Aerosol droplet sizes and velocities from a direct injection nebulizer (DIN) are measured with radial and axial spatial resolution by phase Doppler particle analysis (PDPA). The droplets on the central axis of the spray become finer and their size becomes more uniform when ≍ 20% methanol is added to the usual aqueous solvent. This could explain why the analyte signal is a maximum at this solvent composition when the DIN is used for inductively coupled plasma-mass spectrometry (ICP-MS). Mean droplet velocities are 12 to 22 ms−1 with standard deviations of ±4 to ±7 ms−1. The outer fringes of the aerosol plume tend to be enriched in large droplets. The Sauter mean diameter ( D3,2) and velocity of the droplets also vary substantially with axial position in the aerosol plume.
Effective Resolution Enhancement of Infrared Microspectroscopic Data by Multiresponse Nonlinear Optimization
Authors: Pell R. J. , McKelvy M. L. , Harthcock M. A.
Published: June 2005

Computational methods are proposed and tested that enhance the spatial resolution of infrared microspectroscopic data collected from multilayer polymeric materials film structures. The data collected from such a structure with the use of an infrared microspectroscopic system are diffraction limited at approximately 10 μm (however, diffraction limits are wavelength dependent); therefore, layers of thickness less than approximately 10 μm give rise to spectra that are mixtures of spectra from surrounding layers. Some authors have even pointed out that this could be the case for areas sampled that were much greater than 10 μm. Factor analysis of the data matrix can reveal the number of spectrally different layers that are present, and the eigenvectors will give an abstract representation of the positional and wavelength information. An algorithm has been devised that uses layer boundary positions, aperture width, and aperture step size to model the positional information from such an experiment. The boundary layer positions may be used as adjustable parameters in a nonlinear optimization problem that fits the positional model to the abstract factor analysis positional data. This algorithm is applied to simulated and real data. Simulation results indicate superior performance in comparison with spectral matching to the raw data, and analysis of real data indicates consistent results as well as the ability to resolve unique spectral features when compared with results from more painstaking data collection experiments.
Detection of Sialic Acid Residues and Studies of Their Organization in Normal and Tumor α1-Acid Glycoproteins as Probed by Surface-Enhanced Raman Spectroscopy
Authors: Sokolov Konstantin V. , Byramova Nargiz E. , Mochalova Larisa V. , Tuzikov Alexander B. , Shiyan Svetlana D. , Bovin Nicolai V. , Nabiev Igor R.
Published: June 2005

Surface-enhanced Raman scattering (SERS) spectra of sialic acid (SA) benzyl, and methyl glycosides as well as natural sialylated glycoproteins from human cells of healthy donors and tumor patients have been analyzed in view of the fact that peripheral fragments of many bioactive glycoconjugates are SA residues. SA residues can be detected by SERS at concentrations as low as 10−6 M. The pattern of interaction of SA with the surface of a silver hydrosol involves the C-8 and C-9 hydroxy groups of SA. SERS spectroscopy is sensitive to changes in the content and type of branching of sialylated sugar chains in sialylglycoproteins. The differences in sialylated sugar-chain organization for α1-acid glycoproteins from healthy donors and tumor patients have been detected by means of SERS spectroscopy. The first example of the detection of SA residues for a suspension of living cells has been presented.
UV Resonance Raman Spectroscopy Using a New cw Laser Source: Convenience and Experimental Simplicity
Authors: Asher Sanford A. , Bormett Richard W. , Chen X. G. , Lemmon Donald H. , Cho Namjun , Peterson Pete , Arrigoni Marco , Spinelli Luis , Cannon Jeff
Published: June 2005

A new laser has been developed which generates hundreds of milliWatts of cw UV power below 260 nm. The laser consists of a small-frame Ar+-ion laser which is intracavity doubled with the use of BBO nonlinear optical crystals. More than 300 mW are available at 244 and 257 nm, while 180, 100, and 30 mW are available at 248, 238, and 228.9 nm, respectively. This laser is an ideal source for UV Raman spectroscopy since it avoids the nonlinear and saturation problems common with the typical pulsed laser excitation sources. It also minimizes thermal sample degradation. We demonstrate the increased spectral signal-to-noise ratios possible due to the ability to focus the cw laser into a small-volume element that can be efficiently imaged into the spectrometer. We demonstrate the ability of this laser to excite Raman spectra of solid samples such as coal-liquid residuals, and point out the utility of the 228.9-nm line for studying aromatic amino acids in proteins. We also demonstrate the ability to selectively study pyrene intercalated into calf thymus DNA.
Influence of the Polymer Matrix on the Bipolar and Radial Droplet Configurations within PDLC Films Examined by Infrared Spectroscopy
Authors: McFarland Coleen A. , Koenig Jack L. , West John L.
Published: June 2005

The influence of the polymer matrix on the liquid crystal droplet configuration within a polymer-dispersed liquid crystal (PDLC) film is studied with the use of infrared spectroscopy. With a change of the polymer from poly( n-butyl methacrylate) to poly(isobutyl methacrylate) with the use of E7 liquid crystal, the droplet configuration changes from bipolar to radial. For both of these PDLC systems with 80:20, 70:30, and 60:40 E7/polymer compositions, the LC droplets grow in diameter with time. The spectroscopic data monitoring the droplet growth are described exponentially. A transition temperature is observed as both types of PDLCs cool, forming droplets by the thermally induced phase-separation technique. The TN-I, transition for the E7/PBMA PDLC appears at 46°C and for the E7/PIBMA PDLC appears at 51°C. Index Headings: FT-IR spectroscopy; Polymer-dispersed liquid crystals (PDLC).
Rheo-Optical Fourier Transform Infrared and Raman Spectroscopy of Polymers
Authors: Hoffmann U. , Pfeifer F. , Okretic S. , Völkl N. , Zahedi M. , Siesler H. W.
Published: June 2005

This article is intended to review recent results of simultaneous mechanical and Fourier transform infrared spectroscopic—so-called rheo-optical—measurements for polymer deformation studies. The technique will also be discussed in terms of the application of Fourier transform near-infrared light-fiber and Raman spectroscopy. Specifically, data on the bidirectional drawing of poly(ethylene terephthalate) and the strain-induced conformational changes of poly(vinylidene fluoride) will be presented.